A control device of the above referenced general type, for example an ABS/ESC assembly, has been designed with a pressure sensor in order to determine the barometric ambient pressure.
Such a pressure sensor has to be integrated within the control device in such a manner that a direct connection to the external space comes about for the purpose of registering the ambient pressure. To this end, an aperture, covered by a flexible membrane in the housing wall of the control device has been provided, via which an exchange of pressure with the environment can take place. In this case, problems with the pressure measurement may occur if water or other substances cover the region of the membrane. One possibility to minimize this impairment of the pressure measurement consists in covering the region of the membrane by means of a protective plate, as proposed in DE 195 44 974 C1.
DE 195 44 974 C1, describes a control device with a printed circuit board which is arranged in a housing and on which a pressure sensor has been arranged. This housing consists of a housing base and a housing cover connected to the housing base in water-tight manner, whereby a flexible membrane has been integrated within the housing cover, in order to enable an exchange of pressure with the environment via this membrane. However, it has not thereby been ensured in all cases of operation of such a control device that the membrane does not become covered by water. In such a case, no pressure measurement could be carried out.
The entire interior space of the housing of this known control device can be used as a pressure chamber or sensor chamber. Since such an interior-space volume is too large for the transmission of pressure, document DE 195 44 974 C1 proposes forming, within the housing, a pressure chamber in which the pressure sensor has exclusively been arranged. In this case, the membrane is located in the region of this pressure chamber. For the purpose of forming such a pressure chamber, a sleeve has been provided which is sealing with respect to the interior space of the control device and which surrounds the pressure sensor in such a manner that only a small volume is available for transmitting pressure.
The object of the present invention consists in designing the aforementioned control device with a pressure sensor in such a manner that the wetting with water of the membrane enabling the exchange of pressure with the environment is prevented under all circumstances.
This object is achieved by a control device with the features described herein.